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u6 Flashcards

1
Q

earths surface is heated unevenly because of…

A

rotation of earth, land and oceans, seasons

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2
Q

heat is moved around the earth via ________

A

water vapour

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3
Q

atmosphere is ___% nitrogen , ___% oxygen and ___% other

A

78% N
21% O
1% other

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4
Q

give layers of earth from land to space direction

A

troposphere, stratosphere, mesosphere, thermosphere, exosphere

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5
Q

what is the definition of “lapse rate”

A

how much the temperature changes over a given height

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6
Q

why does the tropopause shrink near poles but high near equator?

A

because equator = hot air rising expands it

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7
Q

lapse rate of troposphere

A

lose 2ºC of termerparte per 1000 ft height

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8
Q

the average temp of tropopause is _____ and the temp remains _______

A

-56ºC
isothermal (doesn’t change)

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9
Q

the stratosphere height in ft and km
lapse rate/temperature _______,
weather can’t penetrate further than this layer because of _________

A

180 000 ft
50 km
increases to 0º because of heated ozone layer
lack of convection

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10
Q

mesosphere height in ft and km
it has a ____ lapse rate
what type of molecules are found here

A

180 000 to 275 000 ft
50-80 km
positive (temp decreases with height)
light gases

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11
Q

thermosphere height starts at
____ lapse rate
why high temperatures?

A

100 km
negative (temp increases with altitude)
intense solar radiation

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12
Q

exosphere height
pressure is like a ________

A

500 km onward
vacuum

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13
Q

standard atmosphere (ISA)
pressure
temperate
pressure decrease per 1000 ft
termparteu decrease per 1000 ft
moisture?
rain?

A

29.92 inHg
15ºC
- 1 inHg drop per 1000 ft
- 2ºC drop per 1000 ft
dry air mass
no precipitation

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14
Q

what is station pressure
does a low or high altitude station have higher pressure

A

weight of the column of air extending upwards from station to atmosphere
low altitude because more air molecules within column

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15
Q

what is mean sea level (MSL) pressure

A

pressure of high altitude airport as if it was at sea level

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16
Q

what are isobars and why are they drawn on a map
they are drawn to be _____ hectopascals apart

A

connect locations of equal pressure
4 hectopascals

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17
Q

isobars close together = _____ pressure difference = _____ flow of air

A

large
fast

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18
Q

high pressure centre:
- air is ______
- flow/rotates:
- weather:

A

sinking
rotates clockwise and outward (anticyclone)
good weather

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19
Q

low pressure centre:
- air is ______
- flow/rotates:
- weather

A

rising
counter clockwise and inward (cyclone)
bad

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20
Q

what is a trough

A

elongated area of low pressure

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21
Q

what is a ridge

A

longed area of high pressure

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22
Q

what is a col

A

natural reaction between two highs and two lows

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23
Q

from high to low lookout below

what does that mean in terms of TEMP difference

A

temp decrease = air density increases and contracts = don’t need to fly as high to get same amount of lift = plane feels like its at xx height at lower true altitude

so flying from high to low temperature, plane will naturally descend because it feels like its at same altitude as before

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24
Q

from high to low lookout below

what does that mean in terms of PRESSURE difference

A

high pressure to low pressure = air density decreases

so staying at same true altitude, your altimeter will feel like you’re higher than you acc are in the low zone

obstacle clearance?

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25
altimeter setting vs mean sea level (MSL) pressure what do you use each for
altimeter setting = current atmospheric pressure reduced to sea level - for setting plane altimeter MSL pressure = average pressure reduced to sea level over a period of 12h - for flight planning and weather purposes
26
colder than standard temperature puts the plane _____ than the altimeter says
lower
27
for every ___ºC temperature change, we change density altitude by 1000 ft
8ºC
28
heating of the atmosphere by
radiation and conduction
29
heating of the atmosphere by
radiation and conduction
30
variations in heating: diurnal variation, seasonal variation, latitude and topography
diurnal variation - day (convection currents rise/mixing atmosphere). night (cooling) seasonal variation - earth tilt = different heating throughout year latitude = most heating at equator topography = land heats up faster than water
31
variations in heating: diurnal variation, seasonal variation, latitude and topography
diurnal variation - day (convection currents rise/mixing atmosphere). night (cooling) seasonal variation - earth tilt = different heating throughout year latitude = most heating at equator topography = land heats up faster than water
32
3 ways heat is moved around through the atmosphere
conduction convection advection
33
how does compression of air molecules make the surrounding air warmer
when a large parcel of air sinks, its compressed by the increasing air pressure of the lower atmosphere increased pressure = the air warms up
34
3 ways the atmosphere cools
(lack of) radiation = surface cools advection adiabatic cooling
35
dry adiabatic rate
3º per 1000 ft
36
saturated adiabatic rate
1.5º per 1000 ft
37
what is a temperature inversion, what causes it and is it stable?
when the temperature increases with altitude caused by radiation cooling from the surface at night stable
38
what is an isotherm on a map
join places of equal temperature on map
39
the amount of water vapour that air can hold is controlled by the air’s _____
temperature
40
what is the dew point
termperature at a given pressure that the air must be COOLED to in order to reach 100% saturation tells us how much water the atmosphere is currently holding
41
cold or hot air holds more moisture and why
hot because more space for water molecules to fit
42
what is the relative humidity (%)
the amount of water vapour present in the air compared to the amount that this air can hold when its saturated
43
dry vs saturated air has ____% relative humidity
dry air = 0% relative humidity saturated air = 100% relative humidity
44
cooling or adding moisture will ______ relative humidity
increase
45
standard vs environmental lapse rate difference
both are the rate that the temperature changes as altitude increases but standard is theoretical (2º/1000) whereas environmental is measured and changes daily
46
frontal vs orographic vs conventional rainfall
frontal = two air masses/fronts converge orographic = warm air forced over mountain and cools and rain conventional = ground surface is locally heated so it rises cools and rain
47
sleet/ice pellets vs freezing rain
ice pellets = snow drops into warm zone -> melts to rain -> drops in large cold zone -> freeze to ice freezing rain = snow drops into warm zone -> melts to rain -> passes through a very shallow cold zone but doesn’t have time to completely re-freeze so it stays as rain
48
sleet/ice pellets vs freezing rain
ice pellets = snow drops into warm zone -> melts to rain -> drops in large cold zone -> freeze to ice freezing rain = snow drops into warm zone -> melts to rain -> passes through a very shallow cold zone but doesn’t have time to completely re-freeze so it stays as rain
49
hail is frozen rain drops larger than _____
5 mm
50
if the dew point is above freezing, _____ forms if the dew point is below freezing, _____ forms (dew vs frost)
dew frost
51
why does dew/frost form
on a moist day, if the ground cools the air will reach it’s saturation point and need to remove excess moisture
52
why will a parcel of moist air rise faster than a parcel of dry air
moist air has a smaller adiabatic lapse rate than dry adiabatic lapse rate. so the difference between the environmental lapse rate and SALR is larger than ELR and DALR. since there’s a larger temperature difference with the moist air, it will rise quicker
53
T/F: the atmosphere is unstable when the environment cools down faster than a parcel of air
true because the parcel of air will keep rising since the environment is colder than the parcel and the hot parcel will rise
54
stable air: ____ flying ____ visibility ____ precipitation _____ cloud ____ environment lapse rate cause _____
smooth poor steady layer/stratus shallow inversions
55
what increases stable conditions
surface cooling warming at higher altitudes
56
unstable air ____ flying ____ visibility ____ precipitation _____ cloud ____ environment lapse rate can lead to _____
bumpy good showery cumulus steep thunderstorm
57
the greater the ELR, the more atmospheric ______
instability
58
absolute stability
a parcel of air attempts to rise but will always be colder than the air surrounding it DALR and SALR are steeper than ELR = air sunk
59
conditional stability
stability depends on whether air is dry or saturated only when the parcel of air is saturated it can rise DALR is steeper (colder) than ELR = air sunk SALR is shallower (warmer) than ELR = air rises
60
absolute instability
parcel of air is always warmer than the outside temp so it always rises DALR and SALR are shallower (warmer) than ELR = air rises
61
potential instability
air is initially cold/stable and environment is warm so it’s not moving. whacky weather triggers at 5000 ft and all of a sudden the environment is extra cold so now the cold air parcel is under colder outside air so that air parcel rises
62
what is solar wind
outermost particles of the sun escape the suns gravity and interacts with earth atmosphere -> northern lights
63
what are sun spots
high energy zones on suns surface that appear dark
64
what are solar flares
occurs when the sunspot releases huge amount of energy
65
the earth’s tilt is ___º and the tilt is responsible for what
23.5º changing seasons
66
equinox vs solstices
equinox = day and night is the same length solstices = day or night is the longest during the year
67
what is light spreading
sunlight in the winter is spread over a large area because the sun passes through the atmosphere at a lower angle = less heat received by earth per square inch
68
what is atmospheric scattering
as sun passes through atmosphere, particles of gas and dust scatter the light most scattering near poles = less light directly hits surface least scattering at equator because direct hit
69
why is the north pole always cold
- near winter, earth tilt makes it so that only a few hours of light a day - more light spreading - more atmospheric scattering
70
“SKC”
sky clear
71
FEW clouds
1/8 to 2/8 sky covered
72
SCT clouds cover
3/8 to 4/8 of sky
73
BKN clouds cover
5/8 to 7/8 of sky
74
ceilings exist when sky is _____ or _____
BKN or OVC
75
lenticular clouds
- from mountain waves - flat - top of mountain wave: air rises = cold = condense int
76
rotor clouds - formed by _____ - air is _____
mountain waves violent/turbulent
77
a cap cloud forms over the top of the mountain and extends partially down the leeward slopes. this indicates…
a strong downdraft

PPL (16 decks)

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